Process for treating hydrocarbons



May 5 936- .3, D. SEGUY PROCESS FOR TREAMNQ IYDROCARBONS 2 Sheets-Sheet 1 INVENTOR JEAN DELATTRE sEGuY l TTORI` May 5, 1936. J. D. sEGUY l PROCESS FOR TREATING HYDROCARBONS 2 Sheets-Sheet 2 Filed Dec.

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|NVENTOR JEAN DELATTRE SEGUY Patented May s, 1936 UNITED sTATEs u 2,999,459 raocnss Foa mesma mnocannons Jean Delattre Berny, Chicago, Ill.. asslgnor to Universal Oil Products Company, Chicago, Ill., a .corporation yof Delaware Application December 14, 1932, Serial No. 647,076

'Ihis application is a continuation my co-pending applications, Serial Nos. 463,061 and 463,062, filed June 23, 1930. 5'

'I'his invention refers more particularly to the treatment of heavy hydrocarbon oils at elevated temperatures and pressures to. produce therefrom lighter and more valuable hydrocarbon oil fractions.

More specifically the present `invention is concerned with processes wherein hydrocarbon oils or other liquid bituminous materials are sub-'- jected to pyrolytic conversion conditions to produce motor fuels, the by-products of the conversion reactions, to-wit, heavyvresidual products (either solid or liquid) and gases, being utilized directly and efficiently as base materials for the production of further quantities of low boiling hydrocarbons by synthetic processes.

One of the chief problems in the production of gasoline by cracking heavy hydrocarbon oil mixtures is that of increasing the yield of desired low boiling fractions to render the process more economical. The limit of yield in most commercial cracking processes is reached when the,

residual products consist either of coke or extremely high viscosity liquids, the latter requiring special handling when utilized as fuel oil on account of their heavy consistency and tendency to contain suspended -carbonaceous particles which clog the ports of burners. It has been appreciated by those familiar with the cracking process for some time that ii iixed gases could be caused to recombine with the residuals that further quantities of 4motor fuel might` be produced. However, this combination is only efvfected with 'diiilculty due to the stable character ofthe two lay-Products and attempts to-utilize this possibility have met with very little success from acommerclal standpoint.

The present invention is concerned with aprocr ess by the operation of which the undesirable by-products from the cracking process may be economically utilized for the production of increased amounts of low boiling gasoline fractions, the particular features of the process being hereinafter fully disclosed.

In one specific embodiment the inventioncom prises cracking hydrocarbon oils at elevated temperatures and pressures to produce'gasoline, solid or. liquid residues, and fixed gases, condensing'and collecting thev gasoline, suitably treating the residue and xed gases with oxidizing gases and steam to produce proportionedmixtures of carbon monoxide .and hydrogen, subjecting said gas mixtures to catalytic influences to. produce increased 8 Claims. (Cl. 196--49l in part of yields of hydrocarbons, and subjecting theproducts from the catalytic step to fractionation together with the products from the primary cracking step. l

To assist in describing operations characteristic of the process of the invention the attached diagrammatic drawings, Figs. 1 and 2, have been provided, which show, by the use of conventional gures, arrangements of apparatus in' which the process may be conducted.

Referring to Fig. 1 of the drawings, a plant layout is shown in which the cracking stage may be carried to the production of sona residuals.' Line I, containing control valve 2, indicates a supply line for whatever heavy hydrocarbon oil may be chosen ior treatment in the process. Such an oil may be the heavier residual portions of petroleum resulting from a primary fractionation thereof, heavy distillates from the same source or analogous hydrocarbon mixtures from other natural or artificial bituminous materials such as coal tars, shale oils, asphalts, etc. These chargingoils may be taken by charging pump 3 and discharged through a line I, containing a control valve 5, into a fractionator 6 which lreceives conversion products from both the crack-Y y ing step-'"and the'synthetic conversion step, the

raw oil` introduced coming into direct contact with the reaction products, assisting in their' fractionation by its cooling action and being itself preheated and stripped of light fractions. To fur-l pressure pump I3 and Ldischarged in turn through a line I4, containing a control valve I 5, and a line I6, containing control valve I1, to a heating element 20. To permitl the diversion of any or "all of the charging oil around the fractionator and its direct feed to the heating zone a by-pass line I8, containing control valve I 9, is preferably provided so that different rates of feed to. the

-fractionator may be employed and the dephlegmating action better controlled. .During passage through heating element 20, which may be of any suitable type disposed to receive heat from a furnace ZI, the temperaturel and pressure are brought to the optimum point for producing desired conversions and the products of the heating are then preferably discharged through a transfer line 22 having interposed therein a control valve 23 and enter a chamber 24 winch constitutes an enlarged vaporizing or reaction zone in which the reactions of conversion initiated by the heating may be permitted to progress to substantial equilibrium. Conditions are preferably so regulated, however, that the formation of coke is substantially prevented and the residual prod-l ucts which are withdrawn throughline 44 and valve 45 have sufcient fluidity to be handled as liquids. The treatment of these liquids will be described presently.

Temperature and pressure ranges cannot be exactly defined since those required will be dependent upon the character of the combined feed to the heating element and the degree of conversion required. In generaltemperatures`of from 850 to -1050 F. more or less may be employed and superatmospheric pressure from about 100 to 500 pounds per square inch. Vaporous products from the reaction zone may be conducted through vapor line 25, containing a control valve 26, and enter fractionator 6 along with vapors from lines 6| and 8|, these vapors originating in a manner which will later be more fully described.

Vapors from fractfonator 6 which are preferably of approximate gasoline boiling point range may be passed through a vapor line 21, containing a control valve 28, and be condensed during passage through a condenser 29 of proper design, uncondensable gases and gasoline then being conducted through a line 30, containing control valve 3|, to a receiver and separator 32. Liquid products may be removed through line 33, containing control valve 34, and gases through line 35', which has branch line 35, containing control valve 36, for-the ultimate disposal of such portions of process gases as are not needed and branch line 35", containing control valve 36", for the transfer of fixed gases directly to the second or synthetic stage of the process. Line 35' contains a control valve 36' which permits the reheating of the xed gases by heating element 31 disposed in a furnace 38, the reheated gases then being caused to travel through a line 39,

containing a control valve 40, to the second stage of the process which will be described more at length in succeeding paragraphs. A

The liquid'residuals from reaction zone 24 ar released to coking chambers under reduced 4pressure in which they are further heated if necessary to insure the production of coke of proper quality. The residuals passing through line 44 and valve 45 which receive liquid increments from the synthetic stage from line 95 as will be presently described, may be passed, preferably with pressure reduction, to any one of a -group of multiple coking chambers, designated as 48 y present drawings.

25, in case coking has been effected without pressure reduction or the pressure in the reaction zone has been reduced sufficiently through valve 26. When pressure in the coking chambers has been reduced to a point lower than that obtaining in line 25, these vapors will necessarily be recompressed before entering the fractionator (since the latter is preferably maintained at the same approximate pressure as the reaction zone) and to effect this object a valve 59 may be opened while valve 62' is closed and the low pressure vapors admitted to a compressor 60 which is of a capacity adapted to raise the pressure to the desired degree to permit their passage through valve 62 and line 6| to line 25 leading to the fractionator. Coking chambers 48 and 48' are provided with liquid draw lines 49 and 49', respectively, containing valves 50 and 50', for withdrawing liquid accumulations if necessary.

When any one chamber has been filled with coke to the proper point the stream of liquid products from the reaction zone is preferably diverted to another chamber and the coke accumulation in the rst chamber is subjected to the controlled and alternate action of air and steam to produce mixtures of carbon monoxide and hydrogen to be used in the synthetic conversion step following. For the admission of steam, lines 5| and 5|', respectively, containing valves 52 and 52' are provided. correspondingly, lines 53 and 53', respectively, containing valves 54 and 54' are provided for the admission of air. As in the usual water gas plants the coke bed may be preliminarily blasted with air to bring its mean temperature to approximately 2000" F. during which period the gases produced are best released from the system and utilized as fuel since they will consist primarily of oxides of carbon and of steam, these mixtures not being suitable for the subsequent syntheses. After the air blasting, steam may be turned in in place of the air to eiect the usual Water gas reactions.

As a matter of economy the low heating value producer gases formed during the blasting period may be utilized to heat chambers that are in the coke-forming stage.

The water gas mixtures thus formed in the chambers may be passed through lines 63 or 63', respectively, containing valves 64 and 64',

and enter a header 65 leading to a compressor 66. This compressor is preferably of a type adapted to produce high pressures upon gas mixtures of the order of 1000 to 3000 pounds per square inch, since good yields of low boiling hydrocarbons are frequently obtained when operating at these high pressures.V Owing to the two facts that on the one hand the water gas mixtures coming from the coke chambers are usually at too high a temperature for eiiicient catalytic hvdrocarbon synthesis and that on the other handadditional temperature rise occurs when these low pressure gasesV are compressed, it is in most cases advisable to cool the gases either prior to or after their recompression, though means for effecting this cooling are not shown in the In addition, it is generally easier to design a compressor for cool than for hot gases.

YThe gases discharged from compressor 65 may pass to the catalytic chamber 16 by way of line 'B1/containing control valve 68, and line 15, containing control valve if the temperature is at the right point or if necessary they may be a line 69, containing a control valve 10, may serve to divert the gas stream through the, heating element, line 13, containing control valve 14, connecting the heating element with line 15.

Prior to' the admission of the water gas mixtures to the catalytic chamber other gases may be added from line 42. For example, if analyses have shown that the proportion of carbon monoxide to hydrogen is not right for obtaining the best results either gas may be pumped `into the line until the correctl proportion is obtained. For v this injection either gas or a proportional vmixture ofv both may be admitted to a pump 99 from a supply line 91, containing a control valve 98, and discharged through a line |00, containing a control valve |00', and through valve 43' in line 42. Reheated processy gases may also be admitted through valve 43 in line 42, such gases having been brought to the required pressure by means of compressor 4|.

Conditions are preferably regulated in catalytic chamber 16 to produce maximum yields of low boiling hydrocarbon products. In general as already stated, high pressures of the order ofy 1000 to 3000 pounds per square inch are advantageous along with moderate temperatures, for example, from 600 to 800 F. approximately. Another stipulation in case predominating yields of hydrocarbons instead of oxygen compounds are desired, is a. ratio of carbon monoxide to hydrogen greater than unity or, in other words, an excess of carbon monoxide over the theoreti-v `usually preferable to desulfurize the gases unless 'an efficient sulfide catalyst is found. Furthermore, the recycled process gases may be of vafiable composition so that again adjustment of conditions is necessary to secure best results. Provisiorrmay be made for either heating or cooling the catalytic chamber to hold the tem- 'perature at an optimum point in any given case.`

In. general the reactions involved are exothermic so that exterior cooling is generally necessary for good control. l

Provision is made for discharging both vapor- Y- ous and non-vaporized products from the catalytic chamber. 'The former may be released through a line 11, containing acontrol valve 18, into line 19 preferably with substantial reduction in pressure, line 19. leading in turn to compressor which discharges through line 8| and valve 82 to vapor line 25 entering the fractionator of the process, so that the vapcrized products from the catalytic chamber undergo fractionation to produce overhead gasoline fractions and refluxes which are reconverted in the primary f heating stage.

Non-vaporized liquids fromthe catalytic chamber may be released through a line 83 and pass either through a line l83|', containing control valve 84', to a low pressure vaporizer 85 or through a line 83"v and a control valve 84 `to a line 92. In the former event a certain amount of material vaporizable at the reduced pressure n may be released in vaporizer 85 and pass through line 8S, containing control valve 81, into line 19 which was shown to lead'ultimately to the process fracticnator. In the`event that the liquid products from the catalytic chamber are withdrawn through line 83" and .valve 84" they may be either rejected fr`om the process through line 90, containing control valve 9|, or. pass through line 92, containing control valve 9,3, to a pump 94 which has a discharge line 95 containing a control Valve 96, and joining with line 44, thus permitting the return to the coking and gas generating stage of liquid residuals from either the catalytic chamber or the vaporizer since the latter has a bottom draw line 88 containing a control Valve 89 which also leads to pump 94 through line 92 and Valv'e 93.

Referring to Fig. 2, a modified arrangement of plant equipment is again shown diagrammatically, this arrangement permitting the utilization of gases and liquid residuals without subjecting the latter to a coking operation. In general, the operation of the cracking unit constituting the primary stage of the process -is substantially theisame as before but owing to minor.

differences it will be preferable to trace the flows.

Raw oil charging stocks of the same diverse character mentioned inconnection with Fig. 1 may be supplied through a line |0| containing a control valve |02 to charging pump |03 which may discharge the charging oilsveither through a l line |04, containing a control valve |05, to a fractionator |06 or through'a line ||1`, containing a control valve ||8, directly to the heating element which will be presently mentioned.v Portions of relatively cold charging oiladmitted to fractionator |06 assist in the dephlegmation of vapors undergoing fractionation and are stripped of their lighter fractions and preheated. The usual cooling coil shown as may be provided in the top of the fractionator, this coil having an inlet line |09, containing control valve ||0, for, the admission of cooling fluids and'a line |01, containing control'valve |08, for their rejection. Heavier -rei'luxes from .the -fractionator consisting of insulliciently converted intermediate fractions and preheated and stripped raw oil may be passed out of the fractionator through a line H2, containing a control valve ||3, and discharged by a combined feed pump ||4 through aline ||5, containing a control valve I6. heating element l0' disposed to receive heat from a furnace I1'. The heated products which have been treated under conditions substantially Asimilar to those mentioned in connection with Fig.1 may pass through a transfer line I8', containing a control valve ||9', and enter reaction chamber |20 as before. Vapors from the reaction chamber may pass through a line I2 I, containing a control valveA ||2, and enter fractionator |00.

Vapors from the secondary or synthetic conversion stage may 'be admitted through .line |2| from line |50. Vapors of desired boiling point range leaving fractionator |06 may be subjected to the usual condensing and separating operation, such vapors passing through a line |22', containing a control valve |23, through a condenser |24 and aline'|2 5, containing a control valve |26 to receiver |21 in which liquids and fixed gases separate. Line |30, containing control valve |3I, is provided for the withdrawal of liquid fractions Line ||5 leads to the usual and line |28, containing control valve |29 is provided for the 'removal of gases that are not to be utilized further in the process.

Y Liquid residuals from reaction chamber |20 are l preferably. withdrawn through a line |34, con- 4 'taining a control valve |35, to treatment inthe subjected te the emiubiued uetieu er oxidizing 1.5

|14, and 'a portion of the'fnonvaprized 'liquidsv secondary or synthetic conversion stage of the process. For the"removal of 'such -portions of 'these liquids as'c'nnot b'e advantageously treated a branch line' |32, containing a control valvel33, is provided, through which they' 4may be withdrawn to storage or-use asfuel.` The essential difference between the operation` now beingde- .scribed in connection with Fig. 1 and tl 1e one previously 'described in connection withFlg. 2-- may be stated to consist in the factv that the liquid residuals instead vof being coked and gasifled toproduce'gas mixtures for synthetic conversion are gases and steam.in what may be termed a'gas generating .or modiiiedcombustion step.V The liquids from line- |34 are preferably reduced in pressure as they pass through valve- 35 and enter a-header |36 terminating in an atomizer |31 at the entrance to 'combustion zone |38. Regulated amounts of oxidizing-gases such as air or. oxygen may be admittedto header '|35 from a line |39 e containing a control valve |40 andsteam may' be similarly 'admittedthrough a' line |4|, containing a controbvalve |42. Headerv |35 may also rer. ceive a portion orfall of the .iixed gasesof the process from line |13, containing a vcontrol valve 'I'he exact construction of combustion zone |33 is subjectV to considerable variation and as its from the secondaryzsta'ge lfrom line |53.

' exact character is notan essential feature of the present invention it has not been shown in de- Y 4am.v 1u generariis designwiu besimilar to the *types of vapparatus that are employed 'in the 'manufacture of oil gas and` may consist of chambers filled with inert material for the mixing of the reacting constituents and the en trainment of carbon or it may be of tubular design. In any event the portions of liquid and gaseous hydr'o carbons, oxidizinggases and steam are adjusted to, produce most nearly the mixtures'ofcarbon monoxide" and hydrogen which will serve to pro- 1 duce good yields of low boilinghydrocarbons in the synthetic step which follows.

-' The gases from the combustin zone may b 'ej conducted through a line |43, v alve |44 and pum'p or compressor I 44', by means of which they are j supplied, at high` superatmospheric pressure,

through line |43 linto a catalytic chamber' |43,

, -whichfunctions similarly to' the-chamber de. scribed in connection with Eig. 1. As before, carbon monoxide o r hydrogen umay be added. to the gas mixturel to obtain the desired ratio,a line 45, containing control valve |46, serving for the 4admission of carbon monoxide and line |41, 'con'- v taining 'control valve |48, serving for. the admis- 'sion ofhydrogenor other reducing gases.

Recycled processgases may also be admitted from line |15, containing control -valve |13. These gases which come from branch line. |l5contain ing control valves- |56 and li'rmay be either -pumped `directly to 'line |15 through valve |55' l and line |13, orma'y be controllably heated.- In

"` lcase they are heated they may be diverted line |61 leading togheating element' |53 disposed in furnace |13 by\ closing valve |33' and opening valve |53, the heated; gases then being returned to line |13 through -line |1|, contaiing'control valve |12. 1 A

The reactions occurring; in' catalytic chamber- |49 are substantially the same as those when x z 1ixi'.ures Vare treated corresponding to those produced in the Ipreviously described operation and w'ill notbe describedz vapors fromthe catalytic chamber .maylbe'released throughs line |53, containing control valve III.

and leading to line |2| as already mentioned. Residual' liquidsmay be `released through line |51, containing' control valve |53, and 'may be returneddirectly to the controlled; combustion zone by way of line |59, line |63 and control .valve |54 orlmay be submitted to a flashing action 'under reduced pressure by passing Vthem through a line |52, containing control valve |53, to a vaporizer |54. The v'aporizer isprovided with a vapor line |55, containing control Tvalve |56 and joining .with line |53. Heavy liquids'from .the vaporizer may be' withdrawn and also be returned to the controlled combuisl tion zone.' To'permit -thef rejection of liquids from the second stage', a line IGI, contalninga control valve |52 is shown.

'I'he operations of the process as disclosed may `be varied over 4a. considerable range and numero'us examplesvof results obtainable might therethro'ughline |59, containing control valve I ll,-

fore be given. However, twowill serve which show results obtainable by operations conducted in the general mannerdisclosed in connection with Figs. 1 and -,2, respectively. i Referring tn operations conductedsubstannection with Fig. 1 le. Mid-'continent'jtopped crude may be cracked in the primary stage to produce a yield of 60% of 425I F. end pointgaso utilized for blending-with raw oil charging stock coking approximately 55 pounds of coke per barL rel of raw oil. By treating the cokewith steam by theusual methods employed in .water gas manufacture, namely, by alternate blasting with A 'air and treatment with superheated-steam at 'temperatures of from v1800 to 2000 F.,'a gas of the general character'of water gas may be produced, in yield `approximating 25% of the theoretical-".When this mixture 'is treated at tem. peratures of approximately'700 F. and pressures of 1500 pounds' per square inch in the presence of a composite catalystv consisting chiey of finely divided iron and minor amounts o f potassium or sodium carbonate, an additional yield. of light compounds boiling within the range -of motor fuel may be' produced, which calculated back to .a charging oil basis, vmay increase the overall yieldjof gasoline from' the' process' by from 3 to 5%'.

Operations uponthe same charging -oil may be conducted' in accordancewith the process described in Fig. 2, the 'residual liquids from the reaction chamberfbeing treated with steam at high i temperatures: and approximately atmos-l pheric pressure' to produce avgas of the followjig approximate composition:

By subjecting this 'ses mixtu're'taf conversion in the presence ofv selected catalytic mixtures comprising metalsof the iron group such as, for example, nickel reduced at a relativelyh'igh tem perature to render it of suitable emciency, yields tially in accordance with those described in oon- '.line a'iong' with 15% 'of refluxe's which may be for. subsequent operation' gil-.disposed of es ngnt fuel oil.- There may ,be produced byoutside of approximately 10% by weight of the gas may be produced at temperatures in the catalytic chamber of the order of from 500 to 600 F. and l.

pressures of about 100 pounds per square inch.

This step may increase the overall yield of gaso- `line by approximately 2 to 3% which is of denite economic value.

It will be recognized that many types of operation are possible without departing from the scope'of the invention and therefore it is to be understood that the specification and examples given are not to be used in the light ofimposing limitations thereon.

I claim as my invention:

1. A process Vfor producing low boiling liquids from heavy hydrocarbon oil which comprises pressure, and catalysis, synthesizing the carbon monoxide and hydrogen in said independentA zone into condensible vapors under conditions controlled independently of the cracking zone, combining the vapors formed by the synthesis with those formed by the cracking, fractionating Y the commingled vapors to condense heavier fractions thereof and supplying resultant reflux condensate to the cracking zone, and finally condensing the fractionated vapors.

2. A process for producing low boiling liquids from heavy hydrocarbon oil which comprises cracking the oill in a cracking zone thereby forming vapors and unvaporized oil, flash distilling the unvaporized oil by pressure reduction and reducing the same to coke, blowing the coke with air and steam at temperatures adequate to form a gaseous mixture containing carbon monoxide and hydrogen, introducing said mixture to an independent zone maintained Vunder synthesizing conditions of temperature, pressure and catalysis, synthesizing the carbon monoxide and hydrogen in said independent zone into condensible vapors under conditions controlled independently of the cracking zone, combining the vapors formed by the synthesis with those formed by the cracking, fractionating the commingled vapors to condense heavier fractions thereof and supplying resultant reflux condensate to the cracking zone, and finally condensing the fractionated vapors.

3. A process for producing low boiling liquids from heavy hydrocarbon oil which comprises cracking the oil in a cracking zone, separating the cracked oil into vapors and residue, treating such residue with air and steam at temperatures adequate to form a gaseous mixture containing carbon monoxide-and hydrogen, increasing'the pressure on the gaseous mixture and synthesizing the carbon monoxide and hydrogen rcontent thereof into condensible vapors in an independent zone maintained under higher pressure than the cracking zone, combining the vapors formed by the .synthesis with those formed by the cracking, fractionating the commingled vapors to condense heavier fractions thereof and supplying resultant reflux condensate to the cracking zone, and finally condensing the fractionated vapors.

4. A process for producing lower boiling liquids from' heavy hydrocarbon oil which comprises sub- .jecting the oil to cracking conditions of temperature and pressure and separating thev same into vaporsand residue, treating such residue with air and steam at temperatures adequate to form a gaseous mixture containing carbon monoxide and hydrogen, increasing the pressure on said mixture and synthesizing the carbon monoxide and hydrogen content thereof into condensible vapors under higher pressure and at lower temperature thanv prevailing in the cracking step, combining the vapors formed by the synthesis with the first-mentioned vapors and fractionating the resultant mixture to condense heavier fractions thereof, returning such condensed fractions to the cracking step, and nally condensing the fractionated vapors.

5. A process for producing low boiling liquids from heavy hydrocarbon oil which comprises cracking the oil in a cracking zone to form vapors and unvaporized oil,ash distilling the unvaporized oil by pressure reduction, treating resultant flashed residue with air and steam at temperatures adequate to form a gaseous mixture containingcarbon monoxide and hydrogen, fractionating and condensingsaid vapors and separating the incondensible gases therefrom, increasing the pressure on said gaseous mixture and introducing the same and a substantial portion of said incondensible gases into an independent zone, synthesizing the carbon monoxide andhydrogen content of the commingled'gases into condensiblel vapors in the independent zone under conditions controlled independently of the cracking zone, and combining the vapors formed by such synthesis with the first-named vapors prior to fractionation of the latter.

6. A process for producing low boiling liquids from heavy hydrocarbon oil which comprises cracking the oil in a cracking zone to form vapors and unvaporized oil, flash distilling the unvaporized oil by pressure reduction, treating resultant flashed residue with air and steam at temperatures adequate to form a gaseous mixture containing carbon monoxide and hydrogen, fractionating and condensing said vapors, increasing the pressurelon said gaseous mixture and introducing the same into an independent zone, synthesizing the carbon monoxide and hydrogen content of said mixture into condensible vapors in the independent zone under conditions controlled independently ofthe cracking zone, and combining the vapors formed by such synthesis with the first-named vapors prior to fractionation of the latter. y

JEAN DELATI'RE SEGUY. 

